The inventor herein is not aware of any prior art control valves or publications that would anticipate the control valve of the instant invention.
However, even though it is contemplated by the inventor herein that the control valves of this invention have many areas of application, the inventor herein, is skilled in the manufacture of portable lift devices for moving handicapped personnel, has worked to develop a control valve that could also be used by handicapped persons to control movement of the devices that lift and transport them. One of the possible uses of such lifts is in and around bathtubs, pools, spas, physical therapy equipment and the like, all of which contain water wherein the use of an electrically controlled control valve would create a potential hazard for the occupant of the lift device. Thus, this control valve was invented.
Such lift devices can be found in at least U.S. Pat. No. 4,996,728, which issued Mar. 5, 1991 to John Nolan, which is incorporated herein for what it teaches about non-electrically controlled portable personnel lifts.